Vitamins

A vitamin is an organic compound required as a nutrient in small amounts by an organism. Vitamins regulate chemical reactions by which the body converts food into energy and living tissues. They also are essential nutrients for the healthy maintenance of the cells, tissues, and organs that make up a multicellular organism.

Vitamins are classified as either water-soluble or fat-soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E, and K) and 9 water-soluble (8 B vitamins and vitamin C). Water-soluble vitamins dissolve easily in water and are readily excreted from the body with the urine. Because they are not readily stored, consistent daily intake is important. Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids and are more likely to accumulate in the body.

Vitamin A (retinol) is necessary for healthy skin, development of the bones, and good vision. Sources of this vitamin include cod liver oil, yellow, orange and green vegetables, and milk.

Vitamin B_r also called thiamine, is necessary for changing starches and sugars into energy. It is found in meat and whole-grain cereals, rice.

Vitamin B₂ or riboflavin is essential for complicated chemical re­actions that take place during the body’s use of food. Milk, cheese, fish, liver, meat, eggs and green vegetables supply vitamin B_r

Vitamin B₃ is better known as niacin or vitamin PP. Cells need niacin in order to release energy from carbohydrates. Liver, yeast, lean meat, fish, nuts, and legumes contain niacin.

Vitamins B₅ (pantothenic acid), B₆ (pyridoxine) and B₇ (biotin) all play a role in chemical reactions in the body. Many foods contain small amounts of these vitamins, but mainly meat, dairy products, eggs and whole-grain cereals.

Vitamins B_l2 or cobalamin and B₉ (also called folate, folic acid or folacin) are both needed for forming red blood cells and for a healthy nervous system. Vitamin B_|2 is found in animal products, especially liver. Folate is present in green leafy vegetables.

Vitamin C or ascorbic acid is necessary for the maintenance of the ligaments, tendons, and other supportive tissue. It is considered to be the main immune vitamin. It is found in fruits, especially in kiwifruits, oranges and lemons.

Vitamin D or calciferol is necessary for the body’s use of calcium. It is present in cod liver oil and vitamin D-fortified milk.

Vitamin E or tocopherol helps maintain cell membranes. It is one of the known antioxidants. Unrefined vegetable oils, especially wheat germ oil, and whole-grain cereals are especially rich in this vitamin. It is also found in small amounts in most meats, fruits, and vegetables.

Vitamin K (K_t — phylloquinone and K₂~ menaquinone) is neces­sary for proper clotting of the blood. Green leafy vegetables contain vitamin K.

Hence, for the most part, vitamins are obtained with food, but a few are obtained by other means. For example, microorganisms in the intestine — commonly known as ‘gut flora’ — produce vitamins K and B₇ (biotin), while one form of vitamin D is synthesized in the skin with the help of the natural ultraviolet waves of sunlight.

Deficiencies of vitamins are classified as either primary or second­ary. A primary deficiency occurs when an organism does not get enough of the vitamin in its food. A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin, due to a ‘lifestyle factor’, such as smoking, excessive alcohol consumption, or the use of medications that interfere with the absorption or use of the vitamin. People who eat a varied diet are unlikely to develop a severe primary vitamin deficiency. In contrast, restrictive diets have the potential to cause prolonged vitamin defi­ciency, which may result in often painful and potentially deadly dis­eases, such as scurvy (vit C deficit), rickets (vit D), anaemia (vit B₆) and others.

Avitaminosis is any disease caused by chronic or long-term vita­min deficiency or caused by a defect in metabolic conversion, such as tryptophan to niacin. Conversely hypervitaminosis is the syndrome caused by over-retention of fat-soluble vitamins in the body.

Language Development

T] Match the English word combinations with the Ukrainian ones and use them in sentences of your own.

1 organic compound	а підсилювати хімічну реакцію
2 develop from nutrients	b вітамін, що розчинюється у воді

3 facilitate the chemical re­action	с різноманітна дієта
4 deficiency disease	сі органічна сполука
5 water-soluble vitamin	е надлишкова затримка
6 ultraviolet wave of sun­light	1" розвиватися за рахунок поживних речовин
7 over-retention	g вторинний дефіцит
8 secondary deficiency	Ь хвороба, що спричинена недостатнітю харчування
9 varied diet	і ультрафіолетова сонячна хвиля

2

З

Match the vitamins with their chemical names.

1 Vitamin A	a Riboflavin
2 Vitamin Bf	b Pyridoxine
3 Vitamin B2	c Cobalamin
4 Vitamin B3	d Retinol
5 Vitamin B5	e Biotin
6 Vitamin B6	f Ascorbic acid
7 Vitamin B7	g Calciferol
8 Vitamin B,	h Niacin
9 Vitamin B12	i Tocopherol
10 Vitamin C	j Phylloquinone or menaquinone
11 Vitamin D	k Thiamine
12 Vitamin E	1 Folic acid
13 Vitamin K	m Pantothenic acid

Match the sentence beginnings with their endings.

1 Vitamins regulate chemical reac­tions by which	a over-retention of fat-soluble vitamins in the body.
2 Vitamins are essential nutrients for the healthy maintenance of the cells, tissues, and organs	b are more likely to accumulate in the body and even cause hypervitaminosis.
3 Water-soluble vitamins dissolve eas­ily in water, are readily excreted from the body with the urine,	c so they are not stored and need consistent daily intake.

4 Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids and	d the body converts food into energy and living tissues.
5 Nutrients during pregnancy facili­tate the chemical reactions that	e that make up a multicellular organism.
6 A secondary deficiency may be due to an underlying disorder that	f. prevents or limits the absorp­tion or use of the vitamins.
7. Restrictive diets have the potential to cause prolonged vitamin defi­ciency,	g which may result in lots of dangerous diseases.
8 Avitaminosis is any disease caused by chronic or long-term vitamin deficiency	h or caused by a defect in meta­bolic conversion.
9 Hypervitaminosis is the syndrome caused by	i produce skin, bones, muscles and other vital tissues and or­gans.